Chapter 4.23

Matrix 106 Resist Removal System

(Asher)

1.0         Title

Matrix 106 Resist Removal System

2.0         Purpose

The Matrix asher model 106 is a resist removal system designed to effectively remove photoresist (polymer).

3.0         Scope

The system one model 106 asher incorporates closed loop control of vital process parameters, which in turn eliminate the chances of both thermal and electrical damage to IC device in the circuit.

4.0         Applicable Documents

5.0         Definitions and Process Terminology

The Model 106 Matrix asher is a production proven fully automated system which uses "pick and place" wafer transport system allowing individual wafer selection as well as automatic group ashing of resist coated wafers.

5.1     Main Console Assembly

This console consists of several components most important of which is the Operator Control (interface) Panel and Card Reader Modules, see Figure. The operator control panel displays the following options on the CRT:

LOAD            Loads Process from data card.

RUN              Starts the run based on the existing process.

EDIT              Can be used to edit an existing process.

SAVE            Saves the existing process (selected process) to data card.

STANDBY      Puts the machine in the standby state.

5.2     Power Supply Console

RF Generator

DC Supply

AC distribution

Temp/Pressure Control Assembly

N2 distribution Panel

6.0         Safety

7.0         Statistical/ Process Data

8.0         Available Processes, Gases, Process Notes

The Matrix asher utilizes oxygen as a process gas. Plasma containing pure oxygen at moderate pressures produces species that can attack the organic material in the photoresist to form CO, CO2 and H2O. Such bi-products quickly get removed from the surface of the substrate and out of the process chamber eventually leaving the substrate free of photoresist. The oxygen plasma is highly selective does not attack Si, SiO2 or Aluminum make it ideal for resist removal application.

9.0         Equipment Operation

9.1     Loading Recipes

Recipes are stored on thin cards. The standard ash recipe should be available on the machine, unless overwritten by recipe download procedure. The standard recipe noted below could remove 1 µm of photoresist / minute and is set for total ash time of 1.5 minute. You may alter the time in the recipe to satisfy thicker resist layer requirement, but should be put back to its original state after the run is completed.

Standard Recipe:

Pressure:          3.75 Torr

MFC1:              40 Percent

MFC2:              0 Percent

MFC3:              0 Percent

RF Power:         400 Watts

Pines:               Down

Endpoint:          Timed

Chuck:              250 Celsius

9.2     Recipe Modification

Recipes can be edited to change the total ash time. Please do not alter the RF total power, unless discussed with process supervisor. You can enter the edit mode by pressing the key located below the "edit" on operator console (main processing screen). Follow the instruction on the screen and use "+" and "-" keys to change the value of selected parameters. More details about current recipe are shown in the appendix section, where number of warm up cycle (2), start up angle and ignition delays ( 420 and 1000, respectively), and the bleed time (5)are define. Please do not change any of these parameters, simply exit out of them, if somehow you end up in the edit mode.

9.3     Processing

(1)     Enable the Matrix asher.

(2)     Check the operator console (CRT) shown in Figure 1 and if in standby mode, then exit by pressing the exit key. Wait until chamber is vented and main operating page is displayed.

(3)     Load your wafers in the designated input cassettes, available at the station (4" or 6").

(4)     Adjust the cassette receiver (stage) to accept your desired wafers size (4" or 6") by placing the input cassette on the stage and adjusting the knobs shown in Figure 2.

(5)     Press "Run" in the run option screen.

(6)     Press "Home" to reset the cassette on the next screen or by the Up and Down key under the move cassette option submenu to position your first wafer in front of the pick and place wafer transport, starting with the lowest desirable wafer slot in the cassette.

(7)     Press Auto or single to start the ash process. This will automatically take all your wafers in or one wafer at a time depending on your selected mode of operation.

(8)     After you are done ashing, remove the wafer cassette.

(9)     Press the standby key to leave the machine in the standby mode with chamber isolated from the atmosphere.

9.4         Descum

You can develop your own descum recipe under staff supervision. Do not alter standard recipe for this application.

 

10.0      Troubleshooting Guidelines

            N/A

11.0      Figures & Schematics

Figure1 - Operating Console (CRT)

Figure 2 - Wafer Stage

12.0   Appendix

 

 Ash Program  (Main Menu)

Pressure

3.75

Torr

MFC1

40

Percent

MFC2

0

Percent

MFC3

0

Percent

RF Power

400

Watts

Pines

Down

 

End Point

Timed

 

Chuck

250

Celsius

First Sub-Menu

Press the run button on Main Menu to get to this screen (do not change anything).

Checking recipe for Process

Step1

is Valid

1Step

Process

Second Sub-Menu

Press exit on first sub-menu to get to this screen (do not change anything).

Would you  like to change

1.       The number of warm up runs?

Press Warm up button to get

to the following menu page.

2.       The start up angle and ignition delay?

Press angle & delay button to get

to this menu page.

3.       The bleed Time?

Press bleed button to get to

the following menu page.

 

Rev. 00 -1/00, S.Parsa

Rev. 01 -11/05, S. Parsa - Added Figures 1 and 2, recipe details in the Appendix and minor changes.